Correction:  sendKeys does not trigger an onchange.   You need to click on another
element to trigger it.   This makes it behave just like a browser.  It would be handy
to have the ability to change an Input's text value and for it to automatically and
immediately fire the onchange.  

HTMLUnit behaves in the same way.    

But Keys (in sendkeys) don't work in HTMLUnit.  My full workaround is now:

if (driver instanceof HtmlUnitDriver)
{
  //HTMLUnit: Keys don't work and clear fires the onChange event!
  //hack is to disable js, call clear and then enable it again
  ((HtmlUnitDriver)driver).setJavascriptEnabled(false);
  element.clear();
  ((HtmlUnitDriver)driver).setJavascriptEnabled(true);
  element.sendKeys(newValue);
}
else
{
  //Firefox.    Clear fires the onChange event, 
  //so send a bunch of backspaces to clear out the input value
  Keys[] keys = new Keys[element.getValue().length()];
  for (int i = 0 ; i < keys.length ; i++)
    keys[i] = Keys.BACK_SPACE;

  element.sendKeys(Keys.chord(keys) + newValue);
}

Instead of repeatedly typing backspace, can you just select the input's value and then

type some more?

element.sendKeys(Keys.chord(Keys.CONTROL, 'a'), 'foobarbaz');

This report is quite old. Is this still a problem in 2.0b1?

Yes, still behaving the same.  I still have to use the workaround described in comment
2.   The bug title and report aren't very accurate though.

I'm trying to get consistent behaviour between HTMLUnit and Firefox drivers

WebElement.sendKeys(text) doesn't fire onchange().   I'm happy with that.
WebElement.clear() fires onchange() if the input had a value.   Is that right?  It
means I can't use it.

org.openqa.selenium.Keys don't work in HTMLUnit  (e.g. BACK_SPACE and TAB).   That
means I have use the above workaround to change the value of a input.

Hi jjim...@googlemail.com,
                           I ma new to Selenium. I have used Selenium IDE, and facing
many problem, error. Searched in web but could not get clear notes or idea about the
error or Selenium can u give any notes about Selenium.

Thanks & Regards 
Sakthy
(sakthy1123@gmail.com)

+1 on this. the Clear() method should not fire any change event until focus is moved
to another element.

.Clear should not trigger onchange event. I belive that if just sendkeys would trigger
events it would do the trick. 

I have login page and when I want to login as different user and call .Clear it triggers
validation that username is not defined and SendKeys do not trigger the validation
again. I have made an workaround that unless you want to empty textbox keeps always
at least 1 character within textbox but it is not clear solution.

I have tries this with Selenium 2.12 (.Net) and Firefox 7.01 and IE 9 same issues with
both browser 

Using version 2.17.0 and still HtmlUnit driver trigger onChange for element.clear()
but not for element.sendKeys(Keys.TAB)...

I'm also hitting this issue with 2.18.0 IE8, FF9 & Chrome16 drivers - a real pain.

With Firefox 5.0.1 and Selenium 2.16.1 is not triggering onchange event for me with
I call element.clear() on an input element. Now you know!

I'm still experiencing that WebElement.Clear() fires onchange()
WebDriver 2.21.0.0
Chrome 19.0.1084.46 m
Firefox 12.0

Will this ever be solved?

As a workaround in C# I've made extension method

public static class WebElementExtensions
{
        public static void ClearWithBackspace(this IWebElement element)
        {
            int length = element.GetAttribute("value").Length;
            element.Click();
            element.SendKeys(Keys.End);
            StringBuilder sb = new StringBuilder();
            int i = 0;
            while(i < length)
            {
                sb.Append(Keys.Backspace);
                ++i;
            };
            element.SendKeys(sb.ToString());
        }
}

web driver 2.23.1 with firefox 12.0.  neither clear(), nor sendKeys() trigger an onchange
event.  Also click() on another input/element after sending keys to an input text box
does NOT trigger an onchange event.

In summary with web driver 2.23.1 and firefox 12 there does not appear to be any way
to trigger an onchange event from a text input element.

Closing this as working as intended.

If you use sendKeys() on an element, that element will still have focus when the command
is finished, so the change event will not fire.  You must change focus to another element
for the change event to fire.

Please do not respond to this bug if you do not get the change event after focusing
on another element - that is a separate issue and you should file a separate bug report.

This problem seems to have (partially) returned.

With WebDriver 2.43.1, calling WebElement.clear() trigger an onchange event (tested
on Firefox 32 and Chrome 37 on Windows 7).
WebElement.sendKeys() does *not* trigger onchange.

Abbreviated test case:

*HTML*

<form>
    Input: <input name="bla" type="text" size="10"
    onchange="this.value=this.value+'X'; console.log('onchange');" />
</form>

*Test*

public void testOnchange() throws Exception {
    driver.get(baseUrl.toString());
    Thread.sleep(5000);
    WebElement input = driver.findElement(By.tagName("input"));
    input.sendKeys("abc");
    Thread.sleep(2000);
    input.clear();
    Thread.sleep(2000);
    assertEquals("", input.getAttribute("value"));
}

Observed result:
First, the text "abc" appears in the field, then the field changes to just "X". Thus
the test fails.

Expected result:
The field should be empty at the end (because nothing triggers an onchange event).

I'm experiencing this issue as well (selenium-java v 2.43.1).

Application has input field:
<input id="search" type="search" placeholder="Enter URL or IP Address" data-bind="event:
{change: $root.searchQuery}" class="input2" maxlength="254s">

The field has a value of "test.com".

If I use field.clear(), an onchange event is kicked off and the page refreshes without
any change of focus.

Here is the method on my pageObject:
    @FindBy(id = "search")
    WebElement searchField;

    @FindBy(id = "submit2")
    WebElement urlSubmit;

    public <T extends BasePage> T urlLookup(String url) throws UnexpectedPageException
{
        searchField.clear();  //Causes page refresh and invalidates elements.
        searchField.sendKeys(url);
        return clickUrlSubmit();
    }